BR102017011101B1 - LIGHT EMISSION DEVICE - Google Patents

Abstract

LIGHT EMISSION DEVICE. The present invention relates to a light emitting device including a light emitting element having a peak emission wavelength of 410nm to 440nm and a phosphor member. The phosphor member includes a first phosphor having a peak emission wavelength of 430 nm to 500 nm and containing an alkaline earth phosphate, a second phosphor having a peak emission wavelength of 440 nm to 550 nm nm and containing at least one of an alkaline earth aluminate and a silicate containing Ca, Mg, and Cl, a third phosphor having a peak emission wavelength of 500 nm to 600 nm and containing a rare earth aluminate, a fourth phosphor having a peak emission wavelength of 610 nm to 650 nm and containing a silicon nitride containing Al and at least one of Sr and Ca, and a fifth phosphor having a peak emission wavelength of 650 nm to 670 nm and containing a fluorogermanate.

Description

CROSS-REFERENCE TO RELATED PATENT APPLICATION

[0001] This application claims the benefit of JP Patent Application No. 2016-104853, filed May 26, 2016 and JP Patent Application No. 2017-092899, filed May 9, 2017, the full disclosure of which is incorporated in this document by reference.

BACKGROUND TECHNICAL FIELD

[0002] The present disclosure relates to a light emitting device.

RELATED TECHNIQUE

[0003] Light-emitting devices configured to emit white light may employ a combination of a light-emitting diode (hereinafter referred to as an "LED") configured to emit blue light and a phosphor to emit light Yellow. Such light emitting devices are configured to emit white light which is a mixture of blue light emitted by blue LEDs and yellow light emitted by phosphors which emit yellow light upon being excited by blue light. Such light emitting devices provide high radiant intensity and high luminance efficacy in a visible light region, but sufficient radiant intensity in a blue-green region and a red region cannot be obtained. For this reason, a further improvement in visual perception of the color of an irradiated object (hereinafter referred to as "color rendering properties") is desirable.

[0004] The evaluation of the color rendering index of light sources is specified by JIS Z8726, in which, color samples of predetermined reflectance (R1 to R15) are measured by a test light and a reference light and the difference in color ΔEi (i is an integer from 1 to 15) of each color is computed, then the special color rendering index (Ri) is calculated. The color rendering index Ri (i is an integer from 1 to 15) has a maximum value of 100. That is, the smaller the difference in chromaticity between the sample light source and the temperature reference light source corresponding color, plus the color rendering index approaches 100. Of the color rendering indexes, an average of R1 to R8 is called the average color rendering index Ra (hereinafter may be referred to as "Ra "), and R9-R15 are called "special color rendering indexes". Of the special color rendering indices are each an evaluation index for red R9, yellow R10, green R11, blue R12, Caucasian skin color R13, treeleaf green R14, and Asian skin color R15.

[0005] In order to improve the color rendering properties of a white light, a light emitting device employing an LED to emit blue light and two kinds of phosphors to emit green light to yellow light, for example, a substance chlorosilicate phosphor and a garnet-type phosphor having Y or Tb have been proposed, for example, in JP Published Translation of PCT International Application No. 2003-535477. In order to further improve the color rendering properties of a light source, a light emitting device further employing a phosphor to emit red light in addition to phosphors to emit green to yellow light has been proposed, for example, in Publication of JP Unexamined Patent Application No. 2008-034188.

SUMMARY

[0006] A light-emitting device includes a light-emitting element having a peak emission wavelength in a range of 410nm to 440nm and a phosphorescent member. The phosphor member includes a first phosphor having a peak emission wavelength in the range of 430 nm to 500 nm and containing an alkaline earth phosphate which has Cl in the composition and is activated with Eu, a second phosphor having a peak emission wavelength in the range from 440 nm to 550 nm and containing at least one of an Eu-activated alkaline earth aluminate and a silicate having Ca, Mg, and Cl in composition and Eu-activated, a third phosphor having a peak emission wavelength in a range of 500 nm to 600 nm and containing a Ce-activated rare earth aluminate, a fourth phosphor having a peak emission wavelength in a range of 610 nm at 650 nm and containing a silicon nitride having Al and at least one of Sr and Ca in the composition and activated with Eu, and a fifth phosphor having a peak emission wavelength in a range of 650 nm nm to 670 nm and containing a Mn-activated fluorogermanate.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a schematic cross-sectional view showing an example of a light emitting device according to an embodiment of the present disclosure.

[0008] Figure 2 is a diagram showing mission spectra of light emitting devices according to examples 1 to 3 and comparative example 1.

[0009] Figure 3 is a diagram showing emission spectra of light emitting devices according to examples 4 to 7 and comparative example 1.

[00010] Figure 4 is a diagram showing emission spectra of light emitting devices according to examples 8 to 11 and comparative example 2.

[00011] Figure 5 is a diagram showing emission spectra of light emitting devices according to examples 12 to 15 and comparative example 2.

[00012] Figure 6 is a diagram showing emission spectra of light emitting devices according to examples 16 to 19 and comparative example 3.

[00013] Figure 7 is a diagram showing emission spectra of light emitting devices according to examples 20 to 23 and comparative example 3.

[00014] Figure 8 is a diagram showing emission spectra of light emitting devices according to example 24 and comparative example 4.

[00015] Figure 9 is a diagram showing emission spectra of light emitting devices according to example 25 and comparative example 5.

DETAILED DESCRIPTION

[00016] In conventional light-emitting devices, the reduction in color differences in yellow, green, red, etc., has been achieved by using phosphorescent substances that can emit yellow light, green light and red light, respectively. However, the emission intensity in a blue region which mainly depends on the light emitting element was difficult to approximate the corresponding reference light source to reduce the color difference in the blue region. The emission intensity in the blue region can be adjusted, for example, by the amounts of phosphorescent substances and/or the addition of a diffusing agent, but satisfactory results have not yet been obtained. Generally, the special R12 color rendering index is greatly affected by emission in the blue wavelength region, and a conventional light emission device tends to result in a low R12 value. In order to obtain a light emitting device with high color rendering properties, the light emitting device is required to produce continuous emission spectrum over a full visible wavelength range, from violet to blue, green to yellow. , and orange to red, similar to sunlight, to increase the R12 value.

[00017] Consequently, a light-emitting element having a peak emission wavelength in a near-ultraviolet region that does not involve calculating the color rendering index can be used in a light-emitting device. However, light in the near-ultraviolet region not only affects humans and objects to be irradiated, but also deteriorates components of the light emitting device and/or causes significant degradation in the luminance effectiveness of the light emitting device.

[00018] According to an embodiment of the present disclosure, a light emitting device of high color rendering properties can be provided.

[00019] Specific examples for obtaining objects will be described below. The present disclosure includes embodiments as described below. A light emitting device includes a light emitting element having a peak emission wavelength in the range of 410 nm to 440 nm and a phosphor member. The phosphor member includes a first phosphor having a peak emission wavelength in the range of 430 nm to 500 nm and containing an alkaline earth phosphate which has Cl in the composition and activated with Eu, a second phosphor having a peak emission wavelength in a range from 440 nm to 550 nm and containing at least one Eu-activated alkaline earth aluminate, and silicate having Ca, Mg, and Cl in the composition and Eu-activated, a third substance phosphor having a peak emission wavelength in a range from 500 nm to 600 nm and containing Ce-activated rare earth aluminate, the fourth phosphor having a peak emission wavelength in a range from 610 nm to 650 nm and containing a silicon nitride having Al and at least one of Sr and Ca in the composition and activated with Eu, and a fifth phosphor having a peak emission wavelength in a range from 650 nm to 6 70 nm and containing a Mn-activated fluorogermanate.

[00020] According to an embodiment of the present disclosure, a light emitting device of high color rendering properties can be provided.

[00021] Preferred embodiments of the present disclosure will be described below with reference to the drawings. The preferred embodiments are intended as illustrative of light emitting devices to give concrete form to technical ideas of the present invention, and the scope of the invention is not limited to those described below. The relationship between color names and chromaticity coordinates, the relationship between the wavelength range of light and the color name of single-color light, and others, in accordance with JIS Z8110. Furthermore, the "content of each component in the composition" indicates that in the case where a plural number of substances corresponding to each component is present in the composition, it refers to a total amount of the plural number of substances in the composition.

LIGHT EMISSION DEVICE

[00022] Figure 1 is a schematic cross-sectional view of a light emitting device 100 according to an embodiment of the present disclosure. The light emitting device 100 includes a light emitting element 10 having a peak emission wavelength in a range of 410 nm to 440 nm and a phosphor member 50. The phosphor member 50 contains a substance phosphor 70 that includes at least five types of phosphors: a first phosphor 71, a second phosphor 72, a third phosphor 73, a fourth phosphor 74, and a fifth phosphor 75. The first phosphor 71 has a peak emission wavelength in a range from 430 nm to 500 nm and contains an alkaline earth phosphate that has Cl in the composition and activated with Eu. The second phosphor 72 has a peak emission wavelength in the range of 440 nm to 550 nm and contains at least one Eu-activated alkaline earth aluminate, and silicate that has Ca, Mg, and Cl in composition and activated he ate. The third phosphor 73 has a peak emission wavelength in the range of 500 nm to 600 nm and contains a Ce-activated rare earth aluminate. The fourth phosphor 74 has a peak emission wavelength in the range of 610 nm to 650 nm and contains a silicon nitride which has Al and at least one of Sr and Ca in the composition and activated with Eu. The fifth phosphor 75 has a peak emission wavelength in the range of 650 nm to 670 nm and contains a Mn-activated fluorogermanate. Furthermore, the phosphor 70 contained in the phosphor member 50 preferably includes the first phosphor 71 having a content in a range of 20% by mass to 80% by mass with respect to a total amount of the phosphor 70.

[00023] With the light emitting element 10 having a specific emission wavelength and the phosphor member 50 containing at least five kinds of specific phosphors with the phosphor 71 of a content of a specific range, a emission spectrum similar to that of the corresponding reference light source can be produced by the light emission device 100. Consequently, high color rendering properties can be obtained. Also, with the use of the light emitting element 10 having a peak emission wavelength and a wavelength range, safety as a light source and high luminance efficacy can be obtained. Furthermore, with the use of a certain light-emitting element 10 and the phosphor member 50 containing the first phosphor 71 of a certain content, particularly special color rendering index R12 can be improved.

[00024] The International Commission on Illumination (CIE) published, in 1986, a guide to the color rendering properties that fluorescent lamps should provide. According to the guide, the preferable average Ra color rendering index for the environments to be illuminated is indicated, for example, Ra from 60 or more to less than 80 for general industrial work areas, etc., 80 or more to less than 90 for homes, hotels, restaurants, shops, offices, schools, hospitals, factories for precision work, etc., 90 or more for clinical examination, museums, etc., requiring high color rendering properties.

[00025] The light emitting device 100 has an Ra of 80 or greater, preferably 90 or greater, and more preferably 95 or greater. Also, the light emitting device 100 has special color rendering indices R9 to R15 of 50 or greater, preferably 70 or greater, and more preferably 90 or greater, respectively. In particular, R12 is, for example, 60 or greater, preferably 75 or greater, and most preferably 90 or greater. Furthermore, a sum of special color rendering indices R9 to R15 (hereinafter may be referred to as Rt) is, for example, 570 or greater, preferably 600 or greater, and more preferably 650 or greater.

[00026] The light emitting device 100 and light of mixed color of light emitted by a light emitting element 10 and fluorescent light emitted by the first phosphor 71, the second phosphor 72, the third phosphor 73, the fourth phosphor 74, and the fifth phosphor 75. For example, with respect to the chromaticity coordinates determined in CIE1931, the mixed light can be adjusted in a range of x=0.00 to 0.50 and y=0.00 to 0 .50, and also in a range of x=0.25 to 0.40 and y=0.25 to 0.40. The correlated color temperature of light emitted by the light emitting device 100 can be, for example, 2000K or greater or 2500K or greater. The correlated color temperature can be 7500K or less, or 7000K or less.

[00027] The light emitting device 100 will be described below with reference to Figure 1. The light emitting device 100 is an example of a surface mounted type light emitting device. The light-emitting device 100 includes a light-emitting element 10 or gallium nitride-based semiconductor compound for emitting short-wavelength visible light (e.g., 380 nm to 485 nm) with an emission wavelength of peak in a range from 410 nm to 440 nm, and a molded body 40 where the light emitting element 10 is mounted. The molded body 40 is formed by integrally molding a first lead 20 and a second lead 30 with a resin piece 42. Alternatively, the molded body 40 can be formed using a known method with the use of ceramics in place of the resin member 42. A recess A defined by a bottom surface and one or more side surfaces is formed in the molded body 40 and the light emitting element 10 is mounted over the bottom surface defining the recess. The light emitting element 10 on positive and negative electrodes and which are electrically connected with the first lead 20 and the second lead 30 through wires 60, respectively. The light emitting element 10 is covered by a phosphor member 50. For example, the phosphor member 50 contains at least five types of phosphors: the first phosphor 71, the second phosphor 72, the third phosphor 73, the fourth phosphor 74, and the fifth phosphor 75, as the phosphor 70 to convert the wavelength of light from the light-emitting element 10.

LIGHT EMISSION ELEMENT 10

[00028] The light emitting element 10 can have a peak emission wavelength in a range from 410 nm to 440 nm, and in view of the luminance effectiveness, in a range from 420 nm to 440 nm is preferable. The use of a light emitting element 10 having a peak emitting wavelength in the range shown above as an excitation light source allows for obtaining a light emitting device 100 for emitting mixed color light from light. emitted from the light emitting element 10 and fluorescent light emitted from the phosphor 70. In addition, the light emitted from the light emitting element 10 to the outside can be used effectively, so that the loss of light emitted from the light emitting device 100 can be reduced and the high efficiency light emitting device 100 can be obtained. In addition, the peak emission wavelength is on one side of the longer wavelength than the near-ultraviolet region and has small ultraviolet content, so that the light-emitting device 100 can provide security as a light source. of light and high luminance efficacy.

[00029] The half-bandwidth of the emission spectrum of the light-emitting element 10 may be 30 nm or less, for example. For the light emitting element 10, a semiconductor light emitting element such as an LED can be used with the use of a semiconductor light emitting element as a light source, a light emitting device 100 having a high Output linearity to introduce high efficiency and having high stability for mechanical impacts can be obtained. For example, a light-emitting element to emit blue light or green light, a nitride-based semiconductor (InxAlYGai-x-YN, where X and Y satisfy y 0<X, 0<Y, and X+Y <1) etc., can be used.

MEMBER OF PHOSPHORESCENT SUBSTANCE 50

[00030] The phosphor member 50 may include, for example, a phosphor 70 and a resin material. The phosphor member 50 includes a phosphor 70 that includes at least one first phosphor 71 for emitting blue light, at least one second phosphor 72 for emitting green light, at least one third phosphor 73 for emitting yellow light, at least one at least one fourth phosphor 74 for emitting red light, and at least one fifth phosphor 75 for emitting deep red light, respectively by absorbing light emitted from the light emitting element 10. The first phosphor 71 to the fifth phosphor phosphorescent 75 has different compositions from each other. The characteristics of the light emitting device 100 such as the luminance efficacy and color rendering properties can be adjusted within a desired range by appropriately selecting the composition ratio of the first phosphor 71 to the fifth phosphor 75.

FIRST PHOSPHORESCENT SUBSTANCE 71

[00031] The first phosphor 71 is a blue light-emitting phosphor that has a peak emission wavelength in a range of 430 nm to 500 nm and contains an alkaline earth phosphate that has Cl in the composition and activated with I. The first phosphor 71 preferably has a composition, for example, represented by formula (1) shown below, more preferably has a composition (1') shown below. With this, the luminance characteristics of the first phosphor 71 described below can be obtained relatively easily. CpC(Ca, Sr, Ba)5(PO4)3(Cl, Br):Eu (1) Ca5(PO4)3Cl:Eu (1')

[00032] The first phosphor 71 has a maximum excitation wavelength in a range of, for example, 360 nm to 440 nm, preferably in a range of 370 nm to 430 nm. The first phosphor 71 can be excited effectively by light in the peak emission wavelength range of the light emission element 10 described above. The first phosphor 71 may have a peak emission wavelength in a range of, for example, 430 nm to 500 nm, and in view of luminance effectiveness, in a range of 440 nm and 480 nm is preferable. Consequently, in the emission spectrum of the light emitting device 100, particularly in the blue region, overlapping between the emission spectrum of the first phosphor 71 and the emission spectra of the light emitting element 10 and the second phosphor 72 can be reduced. Furthermore, by the emission spectrum of the first phosphor 71 and the emission spectrum of the light-emitting element 10, the emission intensity in the blue region of the light-emitting device 100 that has been uniquely assigned to the light-emitting element 10 can easily be made closer to the corresponding reference light source, and thus, the color rendering properties of the light emitting device 100 can be improved. The first phosphor 71 has a width of half the value of the emission spectrum, for example in a range from 29 nm to 49 nm, preferably in a range from 34 nm to 44 nm. In such a range of half-bandwidths, the color purity can be improved and the emission spectrum in the blue region can become closer to the corresponding reference light source, and the color rendering properties of the emitting device light 100 can be further improved.

[00033] For example, when the light emitting device 100 emits light of correlated color temperature in a range of 2000K to 7500K, the percentage content (that is, the amount of the first phosphor/total amount of the phosphors ) of the first phosphor 71 with respect to the total content of the phosphors in the phosphor member 50 may be 20% by mass or greater, preferably 25% by mass or greater, more preferably 40% by mass or greater. The percentage content of the first phosphor 71 may be, for example, 80% by mass or less, preferably 75% by mass or less, more preferably 70% by mass or less. When the percentage content of the first phosphor 71 is in the range described above, the emission spectrum of the light emitting device 100 can be made closer to the corresponding reference light source, so that the color rendering properties of the device of light emission 100 can be further improved.

[00034] For example, when the light emitting device 100 emits light of correlated color temperature in a range of 2,000K to 7,500K, the content ratio of the first phosphor 71 with respect to the third phosphor 73 (i.e. , the first phosphor 71/the third phosphor 73) may be, for example, 0.3 to 7, preferably 0.5 to 6.5, more preferably 0.6 to 6, and most preferably 1.8 to 6 With the ratio of content in range as described above, the emission spectrum of the light emitting device 100 can be made much closer to the corresponding reference light source, so that the color rendering properties of the device of light emission 100 can be further improved.

[00035] In the emission spectrum of the light emitting device 100, with the wavelength on the horizontal axis and the relative intensity on the vertical axis, the ratio of the peak emission intensity of the first phosphor 71 to the intensity peak emission intensity of the light-emitting element 10 (peak emission intensity of the first phosphor 71/peak emission intensity of the light-emitting element 10; hereinafter, the "relation of intensity of light peak emission"), for example, when the light emitting device 100 is configured to emit correlated color temperature light in a range of 2000K to 7500K, for example in a range of 0.15 to 2, preferably in a range of 0.3 to 1.8, and more preferably in a range of 0.5 to 1.5. When the peak emission intensity ratio is in the range as described above, the emission spectrum of the light emission device 100 can be made much closer to the corresponding reference light source, so that the color rendering properties of the light emitting device 100 can be further improved. The peak emission intensity ratio can be calculated so that the maximum value of the emission intensity in a range from 410 nm to 440 nm is assumed to be the peak emission intensity of the light emitting element 10, and the maximum value of the emission intensity in a range from 440 nm to 470 nm is assumed to be the peak emission intensity of the first phosphor 71.

[00036] For example, when the light emitting device 100 emits light of correlated color temperature in a range of 5,500K to 7,500K, the percentage content of the first phosphor 71 may be, for example, 30% by mass or greater, preferably 35% by mass or greater, more preferably 45% by mass or greater. The percentage content of the first phosphor 71 may be, for example, 80% by mass or less, preferably 77% by mass or less, more preferably 75% by mass or less. With the ratio of content in range as described above, the emission spectrum of the light emitting device 100 can be made much closer to the corresponding reference light source, so that the color rendering properties of the light emitting device light 100 can be further improved.

[00037] For example, when the light emitting device 100 emits light of correlated color temperature in a range of 5,500K to 7,500K, the content ratio of the first phosphor 71 with respect to the third phosphor 73 may be, for example 0.9 to 6, preferably 1.5 to 5.9, more preferably 2.5 to 5.85. With the ratio of content in range as described above, the emission spectrum of the light emitting device 100 can be made much closer to the corresponding reference light source, so that the color rendering properties of the light emitting device light 100 can be further improved.

[00038] For example, when the light emitting device 100 emits light of correlated color temperature in a range of 5,500K to 7,500K, the peak ratio emission intensity of the first phosphor 71 with respect to the emitting element of light 10 can be, for example, 0.4 to 1.5, preferably 0.45 to 1.47, more preferably 0.70 to 1.44. When the peak ratio emission intensity is in the range as described above, the emission spectrum of the light emitting device 100 can be made much closer to the corresponding reference light source, so that the color rendering properties of the light emitting device 100 can be further improved.

[00039] For example, when the light emitting device 100 emits light having a correlated color temperature of 4500K or more and less than 5500K, the percentage content of the first phosphor 71 may be, for example, 30% by mass or greater, preferably 45% by mass or greater, more preferably 55% by mass or greater. The percentage content of the first phosphor 71 may be, for example, 80% by mass or less, preferably 78% by mass or less, more preferably 76% by mass or less. With the percentage content in the range as described above, the emission spectrum of the light emitting device 100 can be made much closer to the corresponding reference light source, so that the color rendering properties of the light emitting device 100 can be further improved.

[00040] For example, when the light emitting device 100 emits light having a correlated color temperature of 4500K or more and less than 5500K, the content ratio of the first phosphor 71 with respect to the third phosphor 73 it may be, for example, 0.8 to 5.5, preferably 1.5 to 5.4, more preferably 2 to 5.35. With the ratio of content in the range as described above, the emission spectrum of the light emitting device 100 can be made much closer to the corresponding reference light source, so that the color rendering properties of the light emitting device light 100 can be further improved.

[00041] For example, when the light emitting device 100 emits light having a correlated color temperature of 4500K or more or less than 5500K, the peak ratio emission intensity of the first phosphor 71 with respect to the light emitting element 10 can be, for example, 0.4 to 1.5, preferably 0.5 to 1.45, more preferably 0.6 to 1.4. When the peak ratio emission intensity is in the range as described above, the emission spectrum of the light emitting device 100 can be made much closer to the corresponding reference light source, so that the color rendering properties of the light emitting device 100 can be further improved.

[00042] For example, when the light emitting device 100 emits light having a correlated color temperature of 3500K or more or less than 4500K, the percentage content of the first phosphor 71 may be, for example, 20% by mass or greater, preferably 50% by mass or greater, more preferably 55% by mass or greater. The percentage content of the first phosphor 71 may be, for example, 75% by mass or less, preferably 70% by mass or less, more preferably 64% by mass or less. With the percentage content in the range as described above, the emission spectrum of the light emitting device 100 can be made much closer to the corresponding reference light source, so that the color rendering properties of the light emitting device 100 can be further improved.

[00043] For example, when the light emitting device 100 emits light having a correlated color temperature of 3500K or more or less than 4500K, the content ratio of the first phosphor 71 with respect to the third phosphor 73 it may be, for example, 0.6 to 4.2, preferably 1.8 to 4 more preferably 2.2 to 3.3. With the ratio of content in range as described above, the emission spectrum of the light emitting device 100 can be made much closer to the corresponding reference light source, so that the color rendering properties of the light emitting device light 100 can be further improved.

[00044] For example, when the light emitting device 100 emits light having a correlated color temperature of 3500K or more or less than 4500K, the peak ratio emission intensity of the first phosphor 71 with respect to the light emitting element 10 can be, for example, 0.3 to 1.3, preferably 0.6 to 1.25, more preferably 0.8 to 1.1. When the peak ratio emission intensity is in the range as described above, the emission spectrum of the light emitting device 100 can be made much closer to the corresponding reference light source, so that the color rendering properties of the light emitting device 100 can be further improved.

[00045] For example, when the light emitting device 100 emits light having a correlated color temperature of 2500K or more or less than 3500K, the percentage content of the first phosphor 71 may be 30% by mass or greater , preferably 35% by mass or greater, more preferably 40% by mass or greater. The percentage content of the first phosphor 71 may be, for example, 65% by mass or less, preferably 60% by mass or less, more preferably 55% by mass or less. With the percentage content in the range as described above, the emission spectrum of the light emitting device 100 can be made much closer to the corresponding reference light source, so that the color rendering properties of the light emitting device 100 can be further improved.

[00046] For example, when the light emitting device 100 emits light having a correlated color temperature of 2500K or more or less than 3500K, the content ratio of the first phosphor 71 with respect to the third phosphor 73 it may be, for example, 1 to 4, preferably 1.5 to 3.5, more preferably 1.7 to 2.7. With the ratio of content in range as described above, the emission spectrum of the light emitting device 100 can be made much closer to the corresponding reference light source, so that the color rendering properties of the light emitting device light 100 can be further improved.

[00047] For example, when the light emitting device 100 emits light having a correlated color temperature of 2500K or more or less than 3500K, the peak emission intensity of the first phosphor 71 with respect to the element of light emission 10 can be, for example, 0.2 to 1.4, preferably 0.5 to 1.2, more preferably 0.7 to 1.1. When the peak ratio emission intensity is in the range as described above, the emission spectrum of the light emitting device 100 can be made much closer to the corresponding reference light source, so that the color rendering properties of the light emitting device 100 can be further improved.

SECOND PHOSPHORESCENT SUBSTANCE 72

[00048] The second phosphor 72 is a green light-emitting phosphor that has a peak emission wavelength in a range of 440 nm to 550 nm and contains at least as much of an Eu-activated alkaline earth aluminate or a silicate that has Ca, Mg, and Cl in the composition and activated with Eu. Second phosphor 72 preferably includes at least one alkaline earth aluminate described above. The alkaline earth aluminate preferably has a composition, for example, represented by formula (2a) shown below, more preferably it has a composition (2a') shown below. The silicate preferably has a composition, for example represented by formula (2b) shown below, more preferably has a composition (2b') shown below. With this, the luminance characteristics of the second phosphor 72 described below can be obtained relatively easily. S(Sr, Ca, Ba)4Al14O25:Eu (2a) SSr4Al14O25:Eu (2a') (Ca, Sr, Ba)8MgSi4O16(F, Cl, Br)2:Eu (2b) Ca8MgSi4O16Cl2:Eu (2b')

[00049] When the second phosphor 72 has a content represented by formula (2b), the second phosphor 72 contains at least one element selected from the group consisting of Ca, Sr, and Ba, in which at least Ca is preferably content, and most preferably, a Ca content of Ca, Sr, and Ba, is 90 mol% or greater. The second phosphor 72 contains at least one element selected from the group consisting of F, Cl, and Br, wherein at least Cl is preferably contained, more preferably, a Cl content of F, Cl, and Br is 90 % in mol or greater.

[00050] The second phosphor 72 has a maximum excitation wavelength in a range of, for example, 270 nm to 470 nm, preferably in a range of 370 nm to 460 nm. The second phosphor 72 can be excited effectively by light having a peak emission in the wavelength range of the light emitting element 10 described above.

[00051] When the second phosphor 72 has a composition represented by formula (2a), the peak emission wavelength may be, for example, in a range of 400 nm to 550 nm, preferably in a range of 460 nm and 530 nm. Furthermore, a width of half the value of the emission spectrum can be, for example, in a range from 58 nm to 78 nm, preferably in a range from 63 nm to 73 nm.

[00052] When the second phosphor 72 has a composition represented by formula (2b), the peak emission wavelength may be, for example, in a range of 510 nm to 540 nm, preferably in a range of 520 nm at 530 nm. Furthermore, a width of half the value of the emission spectrum is, for example, in a range from 50 nm to 75 nm, preferably in a range from 58 nm to 68 nm.

[00053] With the use of at least one of such a second phosphor 72, the color purity can be improved and the emission spectrum in the green region can be made closer to the corresponding reference light, and the rendering properties of 100 light-emitting device colors can be further improved.

[00054] For example, when the light emitting device 100 emits light of correlated color temperature in a range of 2,000K to 7,500K, the percentage content of the second phosphor 72 with respect to the total amount of the phosphors in the member of The phosphor 50 (i.e., the amount of second phosphor/total amount of phosphors) can be 0.5% by mass or greater, preferably 0.7% by mass or greater, more preferably 1% by mass or greater. The percentage content of the second phosphor 72 may be 30% by mass or less, preferably 20% by mass or less, more preferably 15% by mass or less.

[00055] For example, when the light emitting device 100 emits light of correlated color temperature in a range of 5,500K to 7,500K, the percentage content of the second phosphor 72 may be 4% by mass or greater, preferably 5 % by mass or greater, more preferably 6% by mass or greater. The percentage content of the second phosphor 72 may be, for example, 20% by mass or less, preferably 13% by mass or less, more preferably 11% by mass or less.

[00056] For example, when the light emitting device 100 emits light having a correlated color temperature of 4500K or more or less than 5500K, the percentage content of the second phosphor 72 may be, for example, 0, 5% by mass or greater, preferably 0.7% by mass or greater, more preferably 1% by mass or greater. The percentage content of the second phosphor 72 may be, for example, 4% by mass or less, more preferably 3% by mass or less, most preferably 2% by mass or less.

[00057] For example, when the light emitting device 100 emits light of correlated color temperature of 3500K or more or less than 4500K, the percentage content of the second phosphor 72 may be, for example, 1.5 % by mass or greater, preferably 2% by mass or greater, more preferably 2.2% by mass or greater. The percentage content of the second phosphor 72 may be, for example, 5% by mass or less, more preferably 3.5% by mass or less, most preferably 3% by mass or less.

[00058] For example, when the light emitting device 100 emits light of correlated color temperature of 2500K or more or less than 3500K, the percentage content of the second phosphor 72 may be, for example, 1.5 % by mass or greater, preferably 2% by mass or greater, more preferably 2.2% by mass or greater. The percentage content of the second phosphor 72 may be, for example, 5% by mass or less, more preferably 3.5% by mass or less, most preferably 3% by mass or less.

[00059] When the percentage content of the second phosphor 72 is in one of the ranges described above, the emission spectrum of the light emitting device 100 in the green region can be made much closer to the corresponding reference light source, so that the color rendering properties of the light emitting device 100 can be further improved.

THIRD PHOSPHORESCENT SUBSTANCE 73

[00060] The third phosphor 73 is a yellow light-emitting phosphorescent substance that has a peak emission wavelength in the range of 500 nm to 600 nm and contains a Ce-activated rare earth aluminate. The third phosphor 73 preferably has a composition represented by formula (3) shown below, more preferably has a composition (3') shown below. With this, the luminance characteristics of the third phosphor 73 described below can be obtained relatively easily. (Y, Lu, Gd)3(Al, Ga)5O12:Ce (3) Y3Al5O12:Ce (3')

[00061] A third phosphor 73 has a maximum excitation wavelength, for example in a range from 220 nm to 490 nm, preferably in a range from 430 nm to 470 nm. The third phosphor 73 can be excited effectively by light in the peak emission wavelength range of light emission element 10 described above. The third phosphor 73 has a peak emission wavelength in the range of 480 nm to 630 nm, more preferably in the range of 500 nm to 560 nm. Consequently, the overlap between the emission spectrum of the third phosphor 73 and the emission spectrum of the second phosphor 72 can be reduced, and a portion of the emission spectrum in the yellow region can be made closer to the corresponding reference light, so so that the color rendering properties of the light emitting device 100 can be further improved. The third phosphor 73 in a width of half the value of the emission spectrum, for example in a range from 95 nm to 115 nm, preferably in a range from 100 nm to 110 nm. In such a range of half-bandwidths, the color purity can be improved and the emission spectrum in the yellow region can be made closer to the corresponding reference light, so that the color rendering properties of the emitting device light 100 can be further improved.

[00062] For example, when the light emitting device 100 emits light of correlated color temperature in a range of 2,000K to 7,500K, the percentage content of the first phosphor 73 with respect to the total content of the phosphors in the member of The phosphor 50 (i.e., the amount of the third phosphor/total amount of the phosphors) may be, for example, 8 wt% or greater, preferably 10 wt% or greater, more preferably 12 wt% or greater. The percentage content of the third phosphor 73 may be, for example, 40% by mass or less, preferably 30% by mass or less, more preferably 25% by mass or less.

[00063] For example, when the light emitting device 100 emits light of correlated color temperature in a range of 5,500K to 7,500K, the percentage content of the third phosphor 73 may be, for example, 8% by mass or greater, preferably 10% by mass or greater, more preferably 12% by mass or greater. The percentage content of the third phosphor 73 may be, for example, 40% by mass or less, preferably 30% by mass or less, more preferably 22% by mass or less.

[00064] For example, when the light emitting device 100 emits light of correlated color temperature 4,500K or more or less than 5,500K, the percentage content of the third phosphor 73 may be, for example, 10% by mass or greater, preferably 12% by mass or greater, more preferably 14% by mass or greater. The percentage content of the third phosphor 73 may be, for example, 45% by mass or less, preferably 30% by mass or less, more preferably 25% by mass or less.

[00065] For example, when the light emitting device 100 emits light of correlated color temperature 3,500K or more or less than 4,500K, the percentage content of the third phosphor 73 may be, for example, 10% by mass or greater, preferably 15% by mass or greater, more preferably 17.5% by mass or greater. The percentage content of the third phosphor 73 may be, for example, 50% by mass or less, preferably 35% by mass or less, more preferably 25% by mass or less.

[00066] For example, when the light emitting device 100 emits light of correlated color temperature 2,500K or more or less than 3,500K, the percentage content of the third phosphor 73 may be, for example, 15% by mass or greater, preferably 17.5% by mass or greater, more preferably 20% by mass or greater. The percentage content of the third phosphor 73 may be, for example, 40% by mass or less, preferably 30% by mass or less, more preferably 25% by mass or less.

[00067] When the percentage content of the third phosphor 73 is in one of the ranges described above, the emission spectrum in the yellow region of the light emitting device 100 can be made much closer to the corresponding reference light source, so that the color rendering properties of the light emitting device 100 can be further improved.

FOURTH PHOSPHORESCENT SUBSTANCE 74

[00068] The fourth phosphor 74 is a phosphor that has a peak emission wavelength in a range of 610 nm to 650 nm and contains a silicon nitride that has Al and at least one of Sr and Ca in the composition and activated with Eu. The fourth phosphor 74 preferably has a composition represented by formula (4) shown below. With this, the luminance characteristics of the fourth phosphor 74 described below can be obtained relatively easily. (Sr, Ca)AlSiN3:Eu (4)

[00069] When the fourth phosphor 74 has the content represented by formula (4), the fourth phosphor 74 contains at least one element selected from the group consisting of Sr and Ca, in which both Sr and Ca are preferably contained, more preferably, of Sr and Ca, 0.8 mol% or greater of Sr is contained. Consequently, the peak emission wavelength of the fourth phosphor 74 can be made into a desired range.

[00070] The fourth phosphor 74 may have a peak emission wavelength in a range of 620 nm to 650 nm, preferably in a range of 630 nm and 645 nm. With the peak emission wavelength equal to or greater than the lower threshold value shown above, insufficient emission intensity can be avoided between the peak emission wavelength of the fourth phosphor 74 and the wavelength emission spectrum of the fifth phosphor 75 to be described below, and a portion of the emission spectrum in the red region can be made closer to the corresponding reference light. With the peak emission wavelength equal to or less than the upper limit value, the overlap between the emission spectrum of the fourth phosphor 74 and the emission spectrum of the fifth phosphor 75 can be reduced and the effect of the emission spectrum of the fifth phosphor 75 can be effectively obtained, and the color rendering properties of the light emitting device 100 can be further improved. The fourth phosphor 74 has a width of half the value of the emission spectrum, for example in a range from 80 nm to 100 nm, preferably in a range from 85 nm to 95 nm. With the half-bandwidth in a band as described above, the overlap of the emission spectrum of the fourth phosphor 74 and the emission spectrum of the fifth phosphor 75 can be reduced, so that the effect of the emission spectrum of the fifth phosphor 75 can be obtained effectively, and the color rendering properties of light emitting device 100 can be further improved.

[00071] For example, when the light emitting device 100 emits light of correlated color temperature in a range of 2,000K to 7,500K, the percentage content of the fourth phosphor 74 with respect to the total content of the phosphors in the member of phosphor 50 (i.e., amount of fourth phosphor 74/total amount of phosphors) may be, for example, 0.5% by mass or greater, preferably 1% by mass or greater, more preferably 1.5% by mass mass or greater. The percentage content of the fourth phosphor 74 may be, for example, 6 wt% or less, preferably 5 wt% or less, more preferably 4 wt% or less.

[00072] For example, when the light emitting device 100 emits light of correlated color temperature in a range of 5,500K to 7,500K, the percentage content of the fourth phosphor 74 may be, for example, 1% by mass or greater, preferably 1.5% by mass or greater, more preferably 2% by mass or greater. The percentage content of the fourth phosphor 74 may be, for example, 6% by mass or less, preferably 4% by mass or less, more preferably 3.8% by mass or less.

[00073] For example, when the light emitting device 100 emits light of correlated color temperature 4,500K or more or less than 5,500K, the percentage content of the fourth phosphor 74 may be, for example, 0.5% by mass or greater, preferably 1% by mass or greater, more preferably 1.5% by mass or greater. The percentage content of the fourth phosphor 74 may be, for example, 3.5% by mass or less, preferably 3% by mass or less, more preferably 2.6% by mass or less.

[00074] For example, when the light emitting device 100 emits light of correlated color temperature 3500K or more or less than 4500K, the percentage content of the fourth phosphor 74 may be, for example, 1% by mass or greater, preferably 1.5% by mass or greater, more preferably 2.27% by mass or greater. The percentage content of the fourth phosphor 74 may be, for example, 4.8% by mass or less, preferably 3.5% by mass or less, more preferably 3% by mass or less.

[00075] For example, when the light emitting device 100 emits light of correlated color temperature 2500K or more or less than 3500K, the percentage content of the fourth phosphor 74 may be, for example, 2.5% by mass or greater, preferably 3% by mass or greater, more preferably 3.2% by mass or greater. The percentage content of the fourth phosphor 74 may be, for example, 4.5% by mass or less, preferably 4% by mass or less, more preferably 3.5% by mass or less.

[00076] When the percentage content of the fourth phosphor 74 is in one of the ranges described above, the emission spectrum in the red range of the light emitting device 100 can be made much closer to the corresponding reference light source, so that the color rendering properties of the light emitting device 100 can be further improved.

FIFTH PHOSPHORESCENT SUBSTANCE 75

[00077] The fifth phosphor 75 is a deep red light-emitting phosphor having a peak emission wavelength in a range of 650 nm to 670 nm and containing a Mn-activated fluorogermanate. The fifth phosphor 75 preferably has a composition of at least one of the fluorogermanates represented by formulas (5a) or (5b) shown below. The peak emission wavelengths of the phosphors represented by formulas (5a) or (5b) are 650 nm or longer, which are longer than other red-emitting phosphors. Consequently, the emission spectrum is a wavelength region that can be effectively made closer to the corresponding reference light, and the color rendering properties of the light emitting device 100 can be further improved. 3.5MgO^0.5MgF2^GeO2:Mn (5a) (x-s)MgO^s/2)Sc2O37MgF2uCaF2(1-t)GeO2(t/2)M'2O3:zMn (5b)

[00078] In formula (5b), x, y, z, s, t, and u satisfy, respectively, 2.0ÍXÍ4.0, 0<y<1.5, 0<z<0.05, 0^s<0 ,5, 0<t<0.5, and 0u<1.5, and further, preferably satisfy y+u<1.5. In formula (5b), Mt is at least one element selected from the group consisting of Al, Ga, and In.

[00079] In formula (5b), 0.05^s<0.3 and 0.05^t<0.3 are preferably satisfied, whereby the luminance can be further improved. The fifth phosphor 75 preferably has a composition represented by formula (5b') shown below. Consequently, the fifth phosphor 75 can be excited effectively by light having a wavelength range that contains the peak emission wavelength of the light emitting element 10 described above. 3.4MgO^0.1Sc2O3^0.5MgF2^0.885GeO2^0.1Ga2O3:0.015Mn (5b')

[00080] The fifth phosphor 75 has a width of half the value of the emission spectrum, for example, 45 nm or less, preferably 40 nm or less. In such half-band bands, the color purity can be improved and the emission spectrum in the red region can be made closer to the corresponding reference light, and the color rendering properties of the light emitting device 100 can be improved. still improved. Furthermore, the fifth phosphor 75 preferably has an emission spectrum where, when the maximum emission intensity is assumed to be 100%, the average emission intensity over a range from 600 nm to 620 nm is, for example, 20% or less, preferably 10% or less. With the peak emission wavelength equal to or less than the upper limit value shown above, the overlap between the emission spectrum of the fifth phosphor 75 to be described below and the emission spectrum of the fourth phosphor 74 can be be reduced, and the effect of the emission spectrum of the fourth phosphor 74 can be obtained effectively, and the color rendering properties of the light emitting device 100 can be further improved.

[00081] For example, when the light emitting device 100 emits light of correlated color temperature in a range of 2,000K to 7,500K, the percentage content of the fifth phosphor 75 with respect to the total content of the phosphors (i.e. , the amount of the fifth phosphor 75/total amount of the phosphors) in the phosphor member 50 may be, for example, 1 wt% or greater, preferably 2 mass % or greater, more preferably 3 mass % or greater . The percentage content of the fifth phosphor 75 may be, for example, 40% by mass or less, preferably 35% by mass or less, more preferably 30% by mass or less.

[00082] For example, when the light emitting device 100 emits light of correlated color temperature in a range of 5,500K to 7,500K, the percentage content of the fifth phosphor 75 may be, for example, 1% by mass or greater, preferably 2% by mass or greater, more preferably 3% by mass or greater. The percentage content of the fifth phosphor 75 may be, for example, 12% by mass or less, preferably 6% by mass or less, more preferably 5.5% by mass or less.

[00083] For example, when the light emitting device 100 emits light of correlated color temperature in a range of 4500K or more or less than 5500K, the percentage content of the fifth phosphor 75 may be, for example, 3% by mass or greater, preferably 5% by mass or greater, more preferably 7% by mass or greater. The percentage content of the fifth phosphor 75 may be, for example, 30% by mass or less, preferably 20% by mass or less, more preferably 15% by mass or less.

[00084] For example, when the light emitting device 100 emits light of correlated color temperature in a range of 3500K or more or less than 4500K, the percentage content of the first phosphor 75 may be, for example, 5% by mass or greater, preferably 8% by mass or greater, more preferably 10% by mass or greater. The percentage content of the fifth phosphor 75 may be, for example, 28 mass% or less, preferably 20 mass% or less, more preferably 16 mass% or less.

[00085] For example, when the light emitting device 100 emits light of correlated color temperature in a range of 2500K or more or less than 3500K, the percentage content of the first phosphor 75 may be, for example, 15% by mass or greater, preferably 18% by mass or greater, more preferably 20% by mass or greater. The percentage content of the fifth phosphor 75 may be, for example, 45% by mass or less, preferably 40% by mass or less, more preferably 30% by mass or less.

[00086] When the percentage content of the fifth phosphor 75 is in one of the ranges described above, the emission spectrum of the light emitting device 100 in the red region can be made much closer to the corresponding reference light source, so that the color rendering properties of the light emitting device 100 can be further improved.

[00087] The phosphor member 50 may optionally contain one or more phosphors other than the first phosphor 71 through the fifth phosphor 75. Examples of other phosphors include Ca3Sc2Si3O12:Ce, CaSc2O4:Ce, (La,Y) 3Si6N11:Ce, (Ca,Sr,Ba)3Si6O9N4:Eu, (Ca,Sr,Ba)3Si6O12N2:Eu, (Ba,Sr,Ca)Si2O2N2:Eu, (Ca, Sr, Ba)2Si5N8:Eu, (Ca ,Sr,Ba)S:Eu, (Ba,Sr,Ca)Ga2S4:Eu, and K2(Si,Ti,Ge)F6:Mn. When the phosphor member 50 contains one or more other phosphors, the percentage contents of these are approximately adjusted to obtain the brightness characteristics obtainable in accordance with the present disclosure. The percentage contents of one or more other phosphors with respect to the total amount of the phosphors can be, for example, 2% by mass or less, preferably 1% by mass or less.

RESIN

[00088] Examples of the resin contained in the phosphor member 50 include thermoplastic resin and thermosetting resin. More specific examples of the thermosetting resin resin include epoxy resin, silicon resin, and modified silicone resin such as epoxy-modified silicon resin.

OTHER COMPONENTS

[00089] The phosphor member 50 may optionally contain one or more components in addition to the phosphor 70 and the resin. Examples of such optional components include a filler material such as silica, barium titanate, titanium oxide, aluminum oxide, and an optical stabilizer, and a coloring agent. When the phosphor member 50 includes one or more other components, the contents thereof can be suitably defined according to the purpose and the like. For example, in the case of including a filler material as the other component, the filler material content can be in a range of 0.01 to 20 pts. in mass with respect to 100 pts. bulk of the resin.

EXAMPLES

[00090] Next, the present invention will be described more specifically with reference to examples, which, however, are not intended to limit the present invention.

PHOSPHORUS SUBSTANCE 70

[00091] Before producing the light emitting device 100, the first phosphor 71 to the fifth phosphor 75 described below were respectively provided.

[00092] For the first phosphor 71, a blue light emitting phosphor having a composition represented by Ca5(PO4)3Cl:Eu and having a peak emission wavelength of about 460 nm (hereinafter may be referred to as "CCA") has been provided.

[00093] For the second phosphor 72, a green light-emitting phosphor having a composition represented by Sr4Al14O25:Eu and having a peak emission wavelength of about 494 nm (hereinafter may be referred to as " SAE") has been provided.

[00094] For the third phosphor 73, a rare earth aluminum garnet phosphor having a composition represented by Y3Al5O12:Ce and having a peak emission wavelength of about 544 nm (hereinafter may be referred to as "YAG") has been provided.

[00095] For the fourth phosphor 74, a red light-emitting phosphor having a composition represented by (Sr,Ca)AlSiN3:Eu and having a peak emission wavelength of about 635 nm (hence hereinafter may be referred to as "SCASN") has been provided.

[00096] For the fifth phosphor 75, a deep red light-emitting phosphor having a composition represented by 3.4MgO^0. 1Sc2Oa^0. 5MgF2^0.885Geθ2^0.1Ga2θs:0.015Mn and having a peak emission wavelength of about 658 nm (hereinafter referred to as "MGF") was provided.

LIGHT EMISSION ELEMENT 10

[00097] For a light emitting element 10, a blue-violet LED having a peak emission wavelength of 430 nm has been provided.

ASSESSMENT

[00098] The emission color chromaticity coordinates, correlated color temperature (Tcp:K), average color rendering index (Ra), special color rendering indexes (R9 to R15) of light emitting devices 100 obtained in the Examples and Comparative Examples were measured. In addition, the sum of the special R9 to R15 color rendering indices (hereafter may be referred to as Rt) was calculated. The average color rendering index and the spot color indices may be collectively referred to as "color rendering indexes". The emission spectrum of the light emitting device 100 was measured using a light beam measuring apparatus equipped with an integral sphere.

EXAMPLE 1 Production of Light Emitting Device 100

[00099] A light emitting device 100 was produced as described below, using a combination of the light emitting element 10 to emit blue-violet light having a peak emission wavelength of 430 nm, the first phosphor 71 (CCA), second phosphor 72 (SAE), third phosphor 73 (YAG), fourth phosphor 74 (SCASN), and fifth phosphor 75 (MGF).

[000100] A phosphor 70 containing the first phosphor 71 (CCA) with a percentage content of 33.3% by mass with respect to the total content of phosphors, and other phosphors with percentage contents with respect to the total content of phosphors as shown in Table 1, respectively, were combined to obtain a correlated color temperature of about 6500 K. The phosphor 70 was added to the silicone resin and mixed and dispersed, and then further smoked to obtain a resin composition containing phosphor . The ratio of percentage contents of first phosphor 71 with respect to the amount of resin (i.e., first phosphor 71/resin) was 15%. Next, the resin composition containing phosphor was injected to enclose the light emitting element 10, and heat was applied to harden the resin composition. Thus, Example 1 of light emitting device 100 was produced.

EXAMPLES 2 to 7

[000101] Examples 2 to 7 of the light emitting device 100 were produced in a similar way as in Example 1, except that the phosphorescent substance contents were adjusted to satisfy the percentage contents shown in Table 1.

COMPARATIVE EXAMPLE 1

[000102] Comparative Example 1 of the light emitting device 100 was produced in a similar manner as in Example 1, except that the first phosphor 71 (CCA) was not used and a combination of the second phosphor 72 (SAE ), the third phosphor 73 (YAG), the fourth phosphor 74 (SCASN), and the fifth phosphor 75 (MGF) was used as the phosphor 70.

TABELA 2

[000103] Examples 1 to 7, and Comparative Example 1 of the light emitting device 100 were evaluated and the results of the evaluation except that the color rendering indexes are shown in Table 1, the results of the color rendering indexes colors are shown in Table 2. TABLE 1

TABLE 2

[000104] As shown in Tables 1 and 2, examples 1 to 7 containing the first phosphor 71 show higher Ra values than Comparative Example 1 which does not contain the first phosphor 71. Furthermore, the examples 1 to 7 show values of 60 or greater for all indices from R9 to R15. On the other hand, Comparative Example 1 which does not contain the first phosphor 71 shows Ra smaller than any examples and R12 of 38 which is much smaller than the examples.

[000105] As shown in Table 1, the correlated color temperatures of examples 1 through 7, and Comparative Example 1 are all in the range of 5500 K to 7500 K. in examples 4, 5, 6, and 7, as shown in Table 1, the percentage contents of the first phosphor 71 with respect to the total content of phosphors were, respectively, in a range of 60% by mass to 80% by mass, and the relationship of contents of the first phosphor 71 with respect to content of the third phosphor 73 was respectively in a range of 2.5 to 6.0. As shown in Table 2, examples 4, 5, 6, and 7 respectively show R12 of 90 or greater, and also Rt of 650 or greater, indicating particularly good color rendering properties.

[000106] Figure 2 shows emission spectra of light emitting devices according to Comparative Example 1 and examples 1 to 3, and figure 3 shows emission spectra of light emitting devices according to Comparative Example 1 and examples 4 to 7, the emission spectrum being normalized to the emission intensity at 530 nm from a 6500K reference light source. The emission spectrum shown in Figure 2 and Figure 3 shows relative emission intensity versus wavelength. In examples 4, 5, 6, and 7, as shown in Table 1, the peak emission intensity ratios of the first phosphor 71 with respect to light emitting element 10 in the emission spectra are, respectively, in a range from 0.7 to 1.5. As shown in Table 2, examples 4, 5, 6, and 7 respectively show R12 of 90 or greater, and also Rt of 650 or greater, indicating particularly good color rendering properties.

EXAMPLES 8 to 15

[000107] Examples 8 to 15 of the light emitting device 100 were produced in a similar way as in Example 1, except that the contents of phosphorescent substances were adjusted to satisfy the ratios of contents shown in Table 3 to adjust the temperature of correlated color at about 5,000K.

COMPARATIVE EXAMPLE 2

[000108] Comparative Example 2 of the light emitting device 100 was produced in a similar manner as in Example 1, except that the first phosphor 71 (CCA) was not used and a combination of the second phosphor 72 (SAE), of the third phosphor 73 (YAG), the fourth phosphor 74 (SCASN), and the fifth phosphor 75 (MGF) was used as the phosphor 70, and the correlated color temperature was adjusted to about 5,000 K.

TABELA 4

[000109] Examples 8 to 15, and Comparative Example 2 of light emitting device 100 have been evaluated and the evaluation results except for the color rendering indices are shown in Table 3, the results of the color rendering indices are shown in Table 4. TABLE 3

TABLE 4

[000110] As seen from Tables 3 and 4, Examples 8 to 15 which contain the first phosphor 71 show higher Ra values than Comparative Example 2 which does not contain the first phosphor 71. Furthermore, Examples 8 to 15 show values of 60 or greater for all indices from R9 to R15. On the other hand, Comparative Example 2 which does not contain the first phosphor 71 shows Ra smaller than any examples and R12 of 35 which is much less than the Examples.

[000111] As shown in Table 3, the correlated color temperature of Examples 8 to 15, and Comparative Example 2 are all in the range of 4500 K to 5500 K. In Examples 10, 11, 12, 13, 14, and 15 , as shown in Table 3, the percentage contents of the first phosphor 71 with respect to the total content of the phosphors were, respectively, in a range of 55% by mass to 80% by mass, and the ratio of the contents of the first phosphor 71 with respect to the content of the third phosphorescent substance 73 were, respectively, in a range of 2.4 to 5.5. As shown in Table 4, examples 10, 11, 12, 13, 14, and 15 respectively show R12 of 90 or greater, and also Rt of 660 or greater, indicating particularly good color rendering properties.

[000112] Figure 4 shows emission spectra of light emitting devices according to Comparative Example 2 and examples 8 to 11, and figure 5 shows emission spectra of light emitting devices according to Comparative Example 2 and Examples 12 to 15, the emission spectra being normalized to the emission intensity at 530 nm from a 5000K reference light source. The emission spectra shown in Figure 4 and Figure 5 show, respectively, the intensity and relative light versus wavelength. In examples 10, 11, 12, 13, 14, and 15, as shown in Table 3, the peak emission intensity ratios of the first phosphor 71 with respect to light emitting element 10 in the emission spectra are , respectively, in a range of 0.6 to 1.5. As shown in Table 4, examples 10, 11, 12, 13, 14, and 15 respectively show R12 of 90 or greater, and also Rt of 660 or greater, indicating particularly good color rendering properties.

EXAMPLES 16 to 23

[000113] Examples 16 to 23 of the light emitting device 100 were produced in a similar way as in Example 1, except that the phosphorescent substance contents were adjusted to satisfy the percentage contents shown in Table 5 to adjust the color temperature correlated at about 4,000K.

COMPARATIVE EXAMPLE 3

[000114] Comparative Example 3 of the light emitting device 100 was produced in a similar manner as in Example 1, except that the first phosphor 71 (CCA) was not used and a combination of the second phosphor 72 (SAE), of the third phosphor 73 (YAG), the fourth phosphor 74 (SCASN), and the fifth phosphor 75 (MGF) was used as the phosphor 70, and the correlated color temperature was set to about 4000K.

TABELA 6

[000115] Examples 16 to 23, and Comparative Example 3 of the light emitting device 100 were evaluated and the results of the evaluation except for the color rendering indices were shown in Table 5, the results of the color rendering indices were shown in Table 6. TABLE 5

TABLE 6

[000116] As seen from Tables 5 and 6, Examples 16 to 23 containing the first phosphor 71 show higher Ra values than Comparative Example 3 which does not contain the first phosphor 71. Furthermore, Examples 16 to 23 show values of 60 or greater for all indices from R9 to R15. On the other hand, Comparative Example 3 which does not contain the first phosphor 71 shows Ra smaller than any examples and R12 of 44 which is much smaller than the Examples.

[000117] As shown in Table 5, the correlated color temperatures of Examples 16 through 23, and Comparative Example 3 are all in the range of 3500 K to 4500 K. In Examples 19, 20, 21, and 22, as shown in Table 5, the percentage contents of the first phosphor 71 with respect to the total content of phosphors were, respectively, in a range of 55% by mass to 70% by mass, and the relationship of contents of the first phosphor 71 with respect to content of the third phosphor 73 was respectively in a range of 2.4 to 3.8. As seen from Table 6, examples 19, 20, 21, and 22 respectively show R12 of 90 or greater, and also Rt of 670 or greater, indicating particularly good color rendering properties.

[000118] Figure 6 shows emission spectra of light emitting devices according to Comparative Example 3 and examples 16 to 19, and figure 7 shows emission spectra of light emitting devices according to Comparative Example 3 and Examples 20 to 23, the emission spectra being normalized to the emission intensity at 530 nm from a 4000K reference light source. The emission spectra shown in Figure 6 and Figure 7 show, respectively, relative emission intensity versus wavelength. In examples 19, 20, and 21, as shown in Table 5, the peak emission intensity ratios of the first phosphor 71 with respect to light emitting element 10 in the emission spectra are, respectively, in a range from 0.8 to 1.1. As seen from Table 6, examples 19, 20, and 21, respectively, show R12 of 97 or greater, and also Rt of 680 or greater, indicating particularly good color rendering properties.

EXAMPLE 24

[000119] Example 24 of the light emitting device 100 was produced in a similar manner as in Example 1, except that the contents of phosphorescent substances were adjusted to satisfy the ratios of contents shown in Table 7 to adjust the correlated color temperature at about 3000K.

COMPARATIVE EXAMPLE 4

[000120] Comparative example 4 of the light emitting device 100 was produced in a similar manner as in Example 1, except that the first phosphor 71 (CCA) was not used and a combination of the second phosphor 72 (SAE), of the third phosphor 73 (YAG), the fourth phosphor 74 (SCASN), and the fifth phosphor 75 (MGF) was used as the phosphor 70, and the correlated color temperature was adjusted to about 3000K.

EXAMPLE 25

[000121] Example 25 of the light emitting device 100 was produced in a similar manner as in Example 1, except that the contents of phosphorescent substances were adjusted to satisfy the ratios of contents shown in Table 7 to adjust the correlated color temperature at about 2,700K.

COMPARATIVE EXAMPLE 5

[000122] Comparative Example 5 of the light emitting device 100 was produced in a similar manner as in Example 1, except that the first phosphor 71 (CCA) was not used and a combination of the second phosphor 72 (SAE), of the third phosphor 73 (YAG), the fourth phosphor 74 (SCASN), and the fifth phosphor 75 (MGF) was used as the phosphor 70, and the correlated color temperature was set to about 2700K.

TABELA 8

[000123] Examples 24 and 25, and comparative examples 4 and 5 of the light emitting device 100 were evaluated and the results of the evaluation except for the color rendering indexes were shown in Table 7, the results of the rendering indexes of colors were shown in Table 8. TABLE 7

TABLE 8

[000124] As seen from tables 7 and 8, examples 24 and 25 that contain the first phosphor 71 show higher Ra values than comparative examples 4 and 5 that do not contain the first phosphor 71. Examples 24 and 25 show values of 90 or greater for all indices R9 through R15. On the other hand, Comparative Example 4 which does not contain the first phosphor 71 shows Ra smaller than Example 24 and R12 of 51 which is much smaller than Example 24. On the other hand, Comparative Example 5 which does not contain the first phosphor 71 shows Ra smaller than Example 25 and R12 of 59 which is much smaller than Example 25.

[000125] As shown in Table 7, the correlated color temperatures of examples 24 and 25, and comparative examples 4 and 5 are all in the range of 2000 K to 3500 K. In examples 24 and 25, as shown in Table 7, the percentage contents of the first phosphor 71 with respect to the total content of phosphors were, respectively, in a range of 40% by mass to 55% by mass, and the relationship of contents of the first phosphor 71 with respect to the content of the third phosphor 73 were, respectively, in a range of 1.9 to 2.5. As seen from Table 8, Examples 24 and 25 respectively show R12 of 90 or greater, and also Rt of 680 or greater, indicating greater color rendering properties than Comparative Examples 4 and 5.

[000126] Figure 8 shows emission spectra of light emitting devices according to Comparative Example 4 and Example 24, and Figure 9 shows emission spectra of light emitting devices according to Comparative Example 5 and Example 25, the emission spectra being normalized to the 530 nm emission intensity of a reference light source. The emission spectra shown in figures 8 and 9 show, respectively, relative emission intensity versus wavelength. In examples 24 and 25, as shown in Table 8, the emission intensity to peak ratios in the emission spectra of the first phosphor 71 with respect to light emitting element 10 are in a range of 0.8 to 1.1 , respectively. In examples 24 and 25, as shown in Table 8, the R12 values are 90 or greater, while the Rt values are 680 or greater, which indicates greater color rendering properties than in comparative examples 4 and 5.

[000127] Light emitting devices according to certain embodiments can be used for lighting devices with good emitting characteristics with an excitation light source of blue light emitting diode or ultraviolet light emitting diode, for LED displays, flash device for cameras, light source for liquid crystal displays, or similar. In particular, light emitting devices according to certain embodiments can be suitably used for lighting devices and light sources which are required with high color rendering properties.

[000128] It should be understood that although the present invention has been described with respect to preferred embodiments thereof, various other embodiments and variants may occur to those skilled in the art, which are within the scope and spirit of the invention, and these other embodiments and variants are intended to be covered by the following embodiments.

[000129] Although the present disclosure has been described with reference to various exemplary embodiments, it should be understood that the words that have been used are words of description and illustration, rather than words of limitation. Changes may be made within the scope of the appended embodiments, as presently stated and as amended, without departing from the scope of the disclosure in its respects. Although the disclosure has been described with reference to particular examples, means and embodiments, the disclosure cannot be intended to be limited to the particulars disclosed, rather the disclosure extends to all functionally equivalent structures, methods and uses as they are within the scope of the attached embodiments.

[000130] One or more examples or embodiments of the disclosure may be referred to herein, individually and/or collectively, by the term "disclosure" merely for convenience and without intending to voluntarily limit the scope of this application to any particular disclosure or inventive concept. Furthermore, although specific examples and embodiments have been illustrated and described herein, it should be appreciated that any subsequent arrangements designed to achieve the same or similar purpose may be substituted for the specific examples or embodiments shown. This disclosure may be intended to cover any and all subsequent adaptations or variations of the various examples and embodiments. Combinations of the above examples and embodiments, and other examples and embodiments not specifically described herein, will be apparent to those skilled in the art when reviewing the description.

[000131] Furthermore, in the Detailed Description above, various aspects may be grouped together or described in a single embodiment for the purpose of expediting disclosure. This disclosure cannot be construed as reflecting an intent that the claimed embodiments need more aspects than are expressly described in each embodiment. Preferably, as the following embodiments reflect, the subject of the invention can be directed to less than all aspects of any of the disclosed embodiments. Accordingly, the following embodiments are incorporated in the Detailed Description, with each embodiment standing by itself as separately defining the claimed subject matter.

[000132] The subject matter disclosed above will be considered illustrative, and not restrictive, and the appended embodiments are intended to cover all such modifications, enhancements, and other embodiments that are within the spirit and scope of the present disclosure. Accordingly, to the fullest extent permitted by law, the scope of the present disclosure may be determined by the broadest permissible interpretation of the following embodiments and their equivalents, and will not be restricted or limited by the above detailed description.

[000133] All publications, patent applications and technical fields mentioned in this report are incorporated herein by reference to the same extent as if each individual publication, patent application or technical standard was specifically and individually indicated to be incorporated by reference.

Claims (21)

1. Light emitting device (100), characterized in that it comprises: a light emitting element (10) having a peak emission wavelength in the range of 410nm to 440nm; and a phosphor member (50), the phosphor member (50) containing a phosphor (70) comprising: a first phosphor (71) having a peak emission wavelength in a range from 430 nm to 500 nm and containing an alkaline earth phosphate, which includes Cl and is activated with Eu; a second phosphor (72) having a peak emission wavelength in the range of 440 nm to 550 nm and containing at least one of an alkaline earth aluminate, which is activated with Eu, and a silicate, which includes Ca, Mg, and Cl e is activated with Eu; a third phosphor (73) having a peak emission wavelength in the range of 500 nm to 600 nm and containing a rare earth aluminate, which is activated with Ce; a fourth phosphor (74) having a peak emission wavelength in the range of 610 nm to 650 nm and containing a silicon nitride, which includes Al and at least one of Sr and Ca and is activated with Eu; and a fifth phosphor (75) having a peak emission wavelength in the range of 650 nm to 670 nm and containing a fluorogermanate, which is activated with Mn, wherein the phosphor member (50) includes the first phosphor (71) having a content in a range of 20% by mass to 80% by mass with respect to a total amount of the phosphor (70), wherein the light emitting device (100) is configured to emit light of a correlated color temperature in a range of 2000K to 7500K and the content ratio of the first phosphor (71) with respect to the third phosphor (73) is 0.3 to 7, and in which the width of half the value of the emission spectrum of the third phosphor (73) is 95 nm to 115 nm. 2. Light emitting device (100), according to claim 1, characterized in that a percentage content of the first phosphorescent substance (71) for a total content of the phosphorescent substance (70) is in a range of 20% by mass to 80% by mass. 3. Light emitting device (100), according to claim 1, characterized in that the light emitting device (100) is configured to emit correlated color temperature light in a range of 5500 K at 7500 K, and a peak optical intensity ratio of the first phosphor (71) to the light emitting element (10) is in a range of 0.4 to 1.5. 4. Light emitting device (100), according to claim 1, characterized in that the light emitting device (100) is configured to emit correlated color temperature light in a range of 4500 K at 5500 K, and a peak optical intensity ratio of the first phosphor (71) to the light emitting element (10) is in a range of 0.4 to 1.5. 5. Light emitting device (100), according to claim 1, characterized in that the light emitting device (100) is configured to emit correlated color temperature light in a range of 3500 K at 4500 K, and a peak optical intensity ratio of the first phosphor (71) to the light emitting element (10) is in a range of 0.3 to 1.3. 6. Light emitting device (100), according to claim 1, characterized in that the light emitting device (100) is configured to emit correlated color temperature light in a range of 2500 K at 3500 K, and a peak optical intensity ratio of the first phosphor (71) to the light emitting element (10) is in a range of 0.2 to 1.4. 7. Light emitting device (100), according to claim 1, characterized in that the light emitting device (100) is configured to emit correlated color temperature light in a range of 5500 K at 7500 K, and a percentage content of the first phosphor (71) with respect to a total content of the phosphor (70) is in a range of 30% by mass to 80% by mass. 8. Light emitting device (100), according to claim 7, characterized in that a content ratio of the first phosphorescent substance (71) with respect to the third phosphorescent substance (73) is in a range of 0.9 to 6. 9. Light emitting device (100), according to claim 1, characterized in that the light emitting device (100) is configured to emit correlated color temperature light in a range of 4500 K at less than 5500 K, and a percentage content of the first phosphor (71) with respect to a total content of the phosphor (70) is in a range of 30% by mass to 80% by mass. 10. Light emitting device (100), according to claim 9, characterized in that a content ratio of the first phosphor (71) with respect to the third phosphor (73) is in a range of 0, 8 to 5.5. 11. Light emitting device (100), according to claim 1, characterized in that the light emitting device (100) is configured to emit correlated color temperature light in a range of 3500 K less than 4500 K, and a percentage content of the first phosphor (71) with respect to a total content of the phosphor (70) is in a range of 20% by mass to 75% by mass. 12. Light emitting device (100), according to claim 11, characterized in that a content ratio of the first phosphorescent substance (71) with respect to the third phosphorescent substance (73) is in a range of 0, 6 to 4.2. 13. Light emitting device (100), according to claim 1, characterized in that the light emitting device (100) is configured to emit correlated color temperature light in a range of 2500 K less of 3500 K, and a percentage content of the first phosphor (71) with respect to a total content of the phosphor (70) is in a range of 40% by mass to 55% by mass. 14. Light emitting device (100), according to claim 13, characterized in that a content ratio of the first phosphorescent substance (71) with respect to the third phosphorescent substance (73) is in a range of 1, 9 to 2.5. 15. Light emitting device (100), according to claim 1, characterized in that the alkaline earth phosphate has a composition represented by formula (1): (Ca, Sr, Ba)5(PO4)3( Cl, Br):I (1). 16. Light emitting device (100), according to claim 1, characterized in that the alkaline earth aluminate has a composition represented by formula (2a) and the silicate has a composition represented by formula (2b): ( Sr, Ca, Ba)4Al14O25:Eu (2a) (Ca, Sr, Ba)8MgSi4O16(F, Cl, Br)2:Eu (2b). 17. Light emitting device (100), according to claim 1, characterized in that the rare earth aluminate has a composition represented by formula (3): (Y, Lu, Gd)3 (Al, Ga )5O12:Ce (3). 18. Light emitting device (100), according to claim 1, characterized in that the silicon nitride has a composition represented by the formula (4): (Sr, Ca)AlSiN3:Eu (4). 19. Light emitting device (100) according to claim 1, characterized in that the fluorogermanate has a composition represented by formula (5a) or formula (5b): 3.5MgO^0.5MgF2^GeO2 :Mn (5a) (x-s)MgO^s/2)Sc2O3yMgF2^CaF2^1-t)GeO2^t/2)Mt2O3:zMn (5b) where, Mt is at least one selected from the group consisting of Al , Ga, and In, and x, y, z, s, t, and u, respectively, satisfy 2gxg4, 0<y<1.5, 0<z<0.05, 0^s<0.5, 0 <t<0.5, and 0u<1.5. 20. Light emitting device (100) according to claim 1, characterized in that the light emitting device (100) is configured to emit light with a special color rendering index R12 of 60 or greater. 21. Light emitting device (100), according to claim 1, characterized in that the light emitting device (100) is configured to emit light with a sum of indices R9 to R15 of rendering of spot colors of 600 or more.

Images